<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
    <div id="app">
        {{msgCon}}
    </div>

</body>
    <script>
        var  app = new Vue({
            el:'#app',
            data:{
                msg:'hello'
            },
            computed:{
                msgCon:function () {
                    return this.msg.toString().toUpperCase()
                }
            }
        })
    </script>
</html>